Prepayment mechanism



Feb. 3, 1942.

A. H. WICKHAM PREPAYMENT MECHANISM Filed Nov. 4, l938 2 Sheets sheet l Feb. 3, 1942. A. H. wlcKHAM PREPAYMENT MECHANISM Filed NOV. 4, 1938 2 Sheets-Sl'leetl 2 Patented Feb. 3, 1942 PREPAYMEN T MECHANISM Alfred Henry Wickham, Enfield, England, assignor to Sangamo Electric Company, Springfield, lll.

Application November 4, 1938, Serial No. 238,720 In Great Britain November 26, 1937 3 Claims.

The present invention relates to prepayment mechanisms for obtaining a supply of a commodity' such as electricity and is more particularly concerned with prepayment mechanisms in which a charge is made which is additional to and independent of the charge made for the commodity consumed. Such additional charge, which is usually known as a fixed charge, can be employed for collecting rent for the hire of apparatus or other like standing charge and includes a constant speed driving element which is effective in reducing the amount of commodity obtainable upon the insertion of a coin.

It will be understood that the constant speed driving element is effective whether or not the commodity is being consumed and it is thus possible that the mechanism may fall into arrears. Before a supply of the commodity can again be obtained, at least at the normal rate of charge, the arrears must be paid off and it is thus important that an accurate measurement of the amount of arrears should be made and that a visible indication of the actual cash value thereof be given to the consumer in crder that he may know the amount of money which is required to be inserted before a supply of commodity can again be obtained.

The principal objects of the present invention are to provide improved arrangements for measuring the amount of arrears and for indicating whether and the extent to which the consumer is in credit or in arrears.

Broadly speaking the principal feature of the invention resides in the provision of a single indicating device for indicating both the extent of any credit due to the consumer and the amount of any arrears that are owing and preferably controlled in such a manner as to indicate the extent of any credit due in commodity values and the amount of any arrears charge in cash values.

The provision of a single indicator for indicating both credit and arrears gives rise to some difliculty particularly when it is arranged to read in some circumstances in cash values and in other circumstances in commodity units. This may be overcome according to another feature cf the invention by arranging that the crediting movement due to coin insertion and debiting movement due to the collection of the fixed charge are transmitted by way of one gear train to the credit registering means and an indicator when the prepayment mechanism is in a credit condition and wherein crediting movement due to coin insertion and debiting movement due to the collection of the fixed charge are transmitted by Way of another gear train to arrears computing means to the same arrears indicator when the prepayment mechanism is in an arrears condition.

The indicator device is preferably in the form of a member, for instance, a pointer movable in either direction from a single zero mark formed, for instance upon a stationary dial plate.

In order that the invention may be more readily understood a iconstructional embodiment thereof will now be described by way of example with reference to the accompanying drawings.

Figures 1A and 1B, taken together, show schematically in perspective one embodiment of my invention.

The arrangement shown comprises four differential gear devices I, II, III and IV. One sun wheel I0 of the differential I is rigidly connected by a sleeve I0 to a gear Wheel II which is arranged to be driven in the direction of the arrow a by the constant speed driving element which serves to assess the fixed charge. The constant speed driving element may, in the case where the invention is applied to the supply of alternating electric current, conveniently be a synchronous electric motor while the driving connection between such element and the gear wheel Il may include some form of gear change device for adjusting the amount of fixed charge which is co1- lected per unit time interval. The other sun wheel I2 of the differential I is rigidly connected by a sleeve I2 to a gear I3 while the planetwheel carrier I4 is secured to a shaft l5 on which the sleeves I0 and I2 are loosely mounted for rotation. The shaft I5 carries a pinion I6 in driving connection through a gear train I'l with a gear I8 rigid with a shaft I9.

One sun wheel 20 of the differential gear II is connected by way of a sleeve 20 to a gear wheel 2l which is arranged in driving connection with a coin mechanism of the device, such as is shown in British Patent No. 445,606, the said gear wheel 2I being rotated in the direction of the arrow b upon insertion of a suitable coin or coins. The other sun wheel 22 is connected by way of a sleeve 22 with a gear 23 which is in mesh with the gear I3 associated with the differential I. The planet wheel carrier 24 of the differential II is rigidly connected to a shaft 25 on which the sleeves 20' and 22 are loosely mounted for rotation. The shaft 25 carries a gear 26 which is in driving connection with a gear 21 through a suitable form of price changeunit, such as is disclosed in British Patent No. 436,914. This price change unit which is preferably located in a readily accessible position may comprise any suitable known form of device by which the gear ratio between the gears and 21 may be varied according to the price which is to be charged for the commodity being supplied.

The gear 21 is secured to a shaft 29whichisprovided with a screw-threaded portion upon which is carried in movable manner a gear wheel 3| provided with an internally threaded hub in engagement with the portion 30 and a toothed periphery in mesh with a long pinion 32 which is carried upon a shaft 33 rigid with a crown wheel 34 adapted for driving engagement with the mechanism which effects metering of the commodity being supplied, for instance the watthour meter mechanism in the case of an electricity prepayment mechanism. The crown wheel 34 is arranged to be driven in the direction of the arrow e by operation of such metering mechanism.

The gear wheel 3| is adapted to be moved backwards and forwards along the threaded portion 30 relatively to the carrier plate 39 in one direction by insertion of coins into the coin mechanism and in the other direction by operation of l the metering mechanism and the fixed charge collector. The gear wheel 3| forms part of a credit-registering device indicated generally by the reference character A and serving to control th'e supply of the commodity in accordance with whether the user is in credit or arrears. The mechanism as shown is adapted to control an electric supply switch and is more specifically shown and described in British Patent No. 414,070. It will not, therefore, be described in greater detail than is necessary for an understanding of the present invention. Brieiiy the device shown comprises a sliding collar 35 movable axially upon the shaft 29 and engaged by one end of a switch controlling arm 35. lar 35 is provided with a flange 31 which can be engaged and held by one end of a catch lever 38 pivotally mounted upon a carrier plate 39 rigid with the shaft 29. The collar 35 is normally urged into the position shown by a spring 40 wh'ere the switch controlled by the arm 36 is opened and can only be retained in the opposite position with the ange 31 held by the end 33h of the lever 38 so long as a pin 4| on the gear 3| is withdrawn from possible contact with the end 38a of the lever 38. Contact between the pin 4| and the end 38a of the lever which is brought about by relative movement between the gear 3| and shaft 29 immediately causes the parts to assume the position shown with' resultant opening of the controlled switch while the 'engagement of a further pin 42 on the gear 3| with a pin 43 on the plate 39 prevents further movement of the said gear in a direction towards the plate 39.

The shaft 29 carries a furtherpinion 44 which is in driving engagement with a gear 45 rigidly connected by a sleeve, not shown, to one sun wheel 46 of the differential gear device IV. 'Ihe other sun wheel 41 of this differential is connect- 'ed by a sleeve 41 to a gear 4B which is in driving connection by way of a gear train 49 with a pinion 50 secured to the shaft 33. The planet wheel carrier 5| ef the differential IV is secured to a shaft 52 on which are loosely mounted the gear 45, sun wheel 46 and connecting sleeve on one side of the planet wheel carrier 5| while on the other side the sun wheel 41, gear 4B and connecting sleeve 41 are loosely mounted on the shaft 52. The shaft 52 is provided with a gear 53 in driving connection through a gear train 54 The coli with a gear wheel 55 connected by way of a sleeve 56' to one sun wheel 56 of the differential gear device III.

The other sun wheel 51 is secured by means of a sleeve 51' to a gear 58 which is in driving connection with the shaft |9 by way of a gear train 59. The planet wheel carrier 5|) of the differential Ill is rigidly connected to a spindle El on which thc gear 55, sun wheel 56 and connecting sleeve 55 are loosely mounted on one side of the planet wheel carrier 60 while on the other side the sun wheel 51, gear 58 and connecting sleeve 51 are loosely mounted on the spindle 6 The spindle 6| extends at its forward end through a dial plate 62 and is provided at that end with a pointer 63 adapted to co-operate with two sets of markings 64 and 55 on the dial plate. The markings 64 serve to indicate the extent of any credit due to the user of the device in the particular units employed for measurement of the commodity whereas the markings 65 serve to indicate the extent of any arrears which are owing by the user in actual cash values. The dial plate 62 is also provided with three further indicators 65 for indicating the total cash value of the coins which have effected operation of the coin mechanism which is in driving connection with the gear wheel 2|. These further indicators 65 are suitably geared together, and are driven by a crown wheel 61 connected in driving relationship with the coin insertion mechanism, such as shown in British Patent No. 445,606, previously referred to.

The end of the spindle 6| opposite to that carrying the pointer 63 is anchored to one end of a helical spring 68 surrounding the spindle, the other end of which spring is secured to a fixed part of the device, for instance a frame plate. The spring 68 is normally tensioned in such a manner that it tends to move the spindle 6| and pointer 63 in a clockwise direction as viewed from the front of the dial plate 52 towards the maximum arrears position.

The gear i8 on the shaft IB is engaged by a further gear wheel 69 secured to a spindle 10 which is carried in suitable bearings in the fixed frame of the device and is provided with a collar 1| secured thereto. Th'e collar 1| is anchored to one end of a helical spring 12 which surrounds the spindle 10 and which is secured at its other end to a fixed part of the device. The collar 1| is also provided with a radially projecting lug 13 which is adapted to engage with a pin projecting from a further lug 14 itself loosely mounted on the spindle 10. This further lug 14 is adapted to engage a pin projecting from another lug 15 which is also loosely mounted on the spindle 10 and is itself arranged to engage a pin projecting from yet a further lug 15. This last lug. is also loosely mounted on the spindle 10 and co-operates with a fixed stop pin 11 carried by a fixed part of the device. This multiple lug structure serves as means for permitting a plurality of revolutions of the spindle 10 with a positive and accurate arrest in either direction, the various lugs and co-operating pins on the next adjacent lug or the fixed pin coming into engagement after the manner shown in the drawings at the end of the permitted amount of movement.

It will be understood that the drawings are schematic in character with various parts omitted or misplaced for the sake of clarity of illustration. For instance all of the shafts o1' spindles are actually carried in suitable bearings formed in supporting frame plates while the gear ratios of and number of gear wheels in the various gear trains may be varied as required from those shown.

The operation of the device as shown is as follows: Assuming that the mechanism is in the Zero credit, zero arrears position where the switch controlled by the arm 36 has just been opened. In this position the various parts are in the position shown with the spring 12 effective to bring the lugs 13 to 1G in engagement with each other and with the stop-pin 11.

Insertion of one or more coins into the coin mechanism connected to gear wheel 2l will cause rotation of the latter and the sun wheelfi of differential II in direction b. The other sun wheel 22 of differential II is held against movement in direction f by reason of locking of sun wheel I of differential I by the fixed chargedeviceand by locking of shaft 19 against rotation in direction d by stop pin 11. In consequence the movement of gear 2l will be transmitted to planet wheel carrier 24 and shaft 25 and then through price change unit28 to shaft 29 which is moved in di rection h to effect an appropriate crediting operation in the credit registering means A. This movement of shaft 29 -is also transmitted to sun wheel 46 of differential IV where the planet wheel carrier I and shaft 52 are rotated owing to locking of the other sun wheel 41 byits connection to the metering device through crown wheel 34. The movement of shaft 52 is transmitted as movement in direction e to sun wheel 55 of differential III. The other sun wheel 51 of this diierential is prevented from rotation in a direction opposite to that of arrow e by the engagement of lugs 13 to 16 on interconnected shaft 1t I" with pin 11. The resultant movement is one of planet carrier EQ and spindle 6I in direction e to cause an appropriate reading interms of units unused on the scale markings 64 by the pointer is yeffectedy t3. This movement of spindle '6I against the action of spring 68. The cash value of the coins inserted in the mechanism will be indicated by an increase in the reading of the indicators 55. The coin insertion operation also causes resetting of the switch tripping means 31, 38 in known manner so that electricity can now be supplied.

Consumption by the metering device connected to the crown wheel 34 will cause movement of the latter in direction c, which movement is .transM mitted by long pinion 32 to gear 3l to cause appropriate decrease in the credit registered in the means A. This movement of pinion 32 is also transmitted to sun wheel 41 of differential IV by gear 50, gear train 49 and gear 48. As sun wheel 46 of this differential is now held by its connection back to coin mechanism through differential II the movement of sun wheel 41, which is in direction 7' will cause similar movement of planet carrier 5I and shaft 52 which in turn act through the differential III to return the spindle (il in a direction opposite to that of the arrow e so as to return the credit registering mechanism and pointer 63 back towards zero position where the switch controlled by the lever will be opened by tripping of catch arm 38 by pin 4I on gear 3I in known manner. vThe return movement of spindle 6I in a direction opposite to that of varrow e is assisted by spring E8.

The constant speed element of the fixed charge collector is also operative in the meantime upon the gear wheel II to cause movement of the latter in the direction a. Taking the case first where the credit registering means A are in credit, then such movement of gear II will be transmitted to sun wheel .22 Vof differential YII through gears .I3 and .23 since `'the planet carrier I4 of' differential I cannot rotate in the desired direction .owing to the resistance of the spring 12 operative upon the interconnected shaft 10. This movementof sun wheel 22, `which is in direction f, causes movement of planet carrier 24 as the other sun wheel 2U is'held by 4engagement with the coin mechanism connected to gear 2l, and thus in turn is transmitted by way `of the price change unit to the shaft .'29 where it acts to move the latter in a ydirection opposite to'that of arrow h to cause appropriate decrease in "the credit registered by the means A. This motion `transmission from the shaft 25 to shaft 29 is similar but in opposite direction to that imparted by operation of the `coin mechanism and in each 'case the original `movement bearing a relation to a cash value is converted into one bearing 'a relation with the actual quantity of electricity which is to be credited or debited `by means of theprice change unit. In similar manner to the coin inserton operation the decrease in 'credit due Vto the fixed charge is indicated by movement of the pointer 63 back towards zero due to motion transmitted through gears 44, 45, differential IV,gears 53, 54 and 55 to differential III.

When the credit registering means reaches zero credit position the pins 42, 43 on the ,gear 3l and carrier plate 39 respectively engage one another and lock the shaft 29 against "further movement in a direction opposite to that of the arrow h. Movement of the constant speed driving element of the fixed charge collecting device to rotate the gear wheel II in the direction a now causes movement of the planet carrier 'I4 of differential I since the other sun wheel I2 cannot rotate in the required direction owing fto the locking of shaft 29 to which it is connected through gears I 3, 23, diierential II #and the price change unit.

The movement of the planet carrier vI4 is in the direction g and causes rotation of the shaft 10 in direction k throughgear I6, gear train I1, .and gears I8 and 69. This movement of the shaft actsto stress the spring 12 and causes movement of ythe lug 13 away from the adjacent lugs `14 to 16. The movement of the planet carrier I4 is also transmitted by Way of gear I6, gear train I1, gear I8, gear train 59 and gear 58 Yto the sun wheel 51 of differential III. As the other sun 'wheel 56 is Aat this moment vheld by its geared connection with the stationary shaft 29 and the now idle metering mechanism, the movement of L the sun wheel 51 causes movement of the planet carrier 60 and spindle GI in a direction opposite to the arrow e whereby the pointer 63 is moved over the scale markings 65 to indicate the amount of the arrears charge in shillings arrears. Since v such movement is effected by way of a geartrain which does not include the price change unit the markings 65 can be made in `actual cash values and will remain unchanged irrespective of any alteration in the price charged per unit for the commodity itself.

The insertion of one or more coins in the coin mechanism while the device is in arrears again causes movement of the gear 2I in direction b but in this case there `are two possible paths over which the movement may be transmitted. The movement may be transmitted as vpreviously 'described by way of the price changeunit to cause a credit setting operation of the registering means A or, alternatively, the movement may fbe transmitted by gear I6, gear train I1 and gears I 8 and 69 to move the spindle 10 in direction d. As this latter movement coincides with the tendency of the now stressed spring 12 to resume its normal unstressed condition, the said movementl of the gear 2l takes this path and any movement due to coin insertion acts to return the lug 13 in the direction d until it is again arrested by the pin 11 through the lugs 14 to 16. This position corresponds to the zero credit, zero debit state and thereafter, as further movement of spindle 10 in direction d is prevented, any further coin insertion movement causes appropriate crediting over the train including the price change unit in the manner previously described. The decrease of the arrears by return of the spindle 1I) in direction d is transmitted to the pointer 63 by Way of gears 59, 5B and differential III as before to give the appropriate reading on the dial plate 62.

By means of the arrangement above described the actual state of either credit or arrears is indicated by a single pointer cO-operating with a single dial thereby avoiding the confusion frequently found to exist in the minds of persons inexperienced in such matters when tWo separate dials are employed.

While the preferred arrangement is that above described it will be clear that the arrangement of duplicate gear trains one for operation during credit state of the apparatus and another during arrears state and both operative upon the same indicator may still be employed when the credit indication is given in coins unused instead of commodity units unused. In this case the gear train between the gears 26 and 21 would be of fixed ratio and the price change unit 28 placed ln the gear train from the metering device to the credit registering mechanism A.

I claim:

1. In a prepayment mechanism for controlling the supply of electricity or like commodity in which arrears due to a fixed charge, credit diminution due to commodity usage and credit increase and arrears removal due to coin insertion are automatically balanced and the net result indicated on a single indicating device, in combination: a first differential gear device including a first pair of sun wheels and a first planet wheel carrier; a second differential gear device including a second pair of sun wheels and a second planet wheel carrier; means operatively interconnecting a sun wheel of said first differential gear device with a sun Wheel of said second differential gear device; arrears registering means comprising first spring means operatively connected to said rst planet Wheel carrier and adapted to be stressed as arrears increase and stop means operatively connected to said first planet wheel carrier to prevent rotation thereof when said prepayment mechanism is in credit condition; a third differential gear device including a third pair of sun Wheels and a third planet wheel carrier; means operatively interconnecting said arrears registering means with a first of said third pair of sun Wheels; second spring means; means operatively interconnecting said second spring means and said third planet Wheel carrier; a single indicating device; means operatively interconnecting said single indicating device with said third planet wheel carrier; a fourth differential gear device including a fourth pair of sun wheels and a fourth planet wheel carrier; means operatively interconnecting said fourth planet wheel carrier with the second of said third pair of sun wheels; and means operatively interconnecting one of said fourth pair of sun wheels with said second planet wheel carrier.

2. In a prepayment mechanism for controlling the supply of electricity or like commodity in which arrears due to a fixed charge, credit diminution due to commodity usage and credit increase and arrears removal due to coin insertion are automatically balanced and the net result indicated on a single indicating device, in combination: a first differential gear device including a first pair of sun wheels and a first planet wheel carrier; a second differential gear device including a second pair of sun Wheels and a second planet Wheel carrier; means operatively interconnecting a sun Wheel of said first differential gear device with a sun Wheel of said second differential gear device; arrears registering means comprising first spring means operatively connected to said first planet wheel carrier and adapted to be tightened as arrears increase and stop means operatively connected to said first planet Wheel carrier to prevent rotation thereof when said prepayment mechanism is in credit condition; a third differential gear device including a third pair of sun `wheels and a third planet wheel carrier; means operatively interconnecting said arrears registering means with a first of said third pair of sun wheels; second spring means; means operatively interconnecting said second spring means and said third planet Wheel carrier; a single indicating device comprising a dial plate, an arrears scale in money units on said dial plate, a credit scale in commodity units on said dial plate, said arrears and credit scales having a common zero point, and a pointer for passing over said dial plate and adjusted to bc at the common zero point when said prepayment mechanism is in the zero credit, Zero arrears condition; means operatively interconnecting said pointer with said third planet wheel carrier; a fourth diiferential gear device including a fourth pair of sun Wheels and a fourth planet Wheel carrier; means operatively interconnecting said fourth planet Wheel carrier with the second of said third pair of sun Wheels; and means operatively interconnecting one of said fourth pair of sun wheels with said second planet wheel carrier.

3. In a prepayment mechanism for controlling the supply of electricity or like commodity in which arrears due to a fixed charge, credit diminution due to commodity usage and credit increase and arrears removal due to coin insertion are automatically balanced and the net result indicated on a single indicating device, in combination: a first differential gear device including a first pair of sun Wheels and a first planet wheel carrier; a second differential gear device includlng a second pair of sun Wheels and a second planet Wheel carrier; means operatively interconnecting a sun wheel of said first differential gear device with a sun wheel of said second dif ferential gear device; arrears registering means comprising first spring means operatively con` nected to said first planet wheel carrier and adapted to be stressed as arrears increase and stop means operatively connected Ato said first planet wheel carrier to prevent rotation thereof when said prepayment mechanism is in credit condition; a third differential gear device includmg a third pair of sun wheels and a third planet Wheel carrier; means operatively interconnecting said arrears registering means with a first of said third pair of sun wheels; second spring means; means operatively interconnecting said said third pair of sun Wheels; a price change unit; means operatively interconnecting said second planet Wheel carrier and said price change unit; and means operatively interconnecting one of said fourth pair of sun Wheels with said price change unit.

ALFRED HENRY WICKHAM. 

